41CV doesn't turn on


My 41CV will occasionally refuse to turn on. The problem started about 10 years ago and about 10 years after I got the calculator. At the time, that was sufficient reason for me to get a 48G. I decided several weeks ago to see if I could resurrect the 41CV. New batteries and a few resets brought it back to life. It did fine for a few weeks, but is now starting to get flaky again.

Based on some of the messages here, I will attempt to see if the problem is with the connections to the display, but I am curious to know if it might be something else.

Any ideas?



just to check for primary information: is your CV a fullnut or a halfnut?

The bad contact the usually causes this sort of problem is more likely to happen in the fullnut type.


Luiz C. Vieira - Brazil


It's a fullnut.



I'm sending you an e-mail with the link for a PDF file that shows how do a fullnut look inside. It's primary target is to show how to remove a fullnut's LCD assy, but you can see one very important thing right in the first page: the "zebra" connector between the separate mainboard and the keyboard PCB. If the hear screws are loose OR the zebra connector shows a bad connection, changes are that opening and cleanning the contacts will be enough.

Let us know if you need more advice.

Best regards.

Luiz C. Vieira - Brazil


Ahn... I wrote a word wrongly.

When reading:

> If the hear screws are loose

please read:

> If the rear screws are loose

I know you understood, I just want to put it right...



Hi, David;

I sent you an e-mail and received this message:


The original message was received at Tue, 4 Mar 2003 02:29:10 -0300
from []

----- The following addresses had transient non-fatal errors -----

----- Transcript of session follows -----
451 <dcschooley@ieee.org>... reply: read error from orion.ieee.org.
<dcschooley@ieee.org>... Deferred: Connection reset by orion.ieee.org.
Warning: message still undelivered after 4 hours
Will keep trying until message is 5 days old

I'm posting my e-mail so you can contact me and I'll send you the e-address so you can download the PDF with mentined images.

Best regards.

Luiz C. Vieira - Brazil


Hello Vieira!

How do you embed a jpeg in your post? I haven't been able to do that here.

Much obliged!




first of all, the image must be available in the www. Then you do this:

[img:www address]

In my case:



There is more here.

Best regards.

Luiz C. Vieira - Brazil


Luiz is correct, that bad connections are the main problem makers. Here's my list in order of most common problems:

  1. Broken posts or case bosses resulting in poor logic board or battery connections.
  2. Corrosion on battery terminals or battery holder.
  3. A dirty ON switch contact.
  4. And, as a last resort, broken solder connections to the LCD. A good visual check can be done with a 5X loupe to see if any soldering is suspect.

(OT) Heh Luiz, is that your font used in the photos? It looks like the 42S pixel ratio?


Hi, Randy;

I'm doing a general cleanup on my stuff so I'll allow others to download some TTF I built. So far, I have the HP41 LCD character set, 82143 printing, Voyager LCD, general keyset (almost all HP calculators) and the HP42S is under development. I have it as ordinary, character font, but it must be a symbol font (I have to redraw everything) to work better under some Windows aplications.

Did I send you the TTF files already? I sent them to so many contributors I don't remember. Please, forgive-me if I forgot this fact.

As soon as it is ready to be used I'm posting the news.

Best regards.

Luiz C. Vieira - Brazil


Hi, all.

The full_halfnut.jpg image shows a mutilated image of the actual TTF characters mentioned previously. This is due to reduction in final image, after adding the TTF characters. Actual characters are exactly the same seen in the calculator's LCD.

Also, some TTF are ready to download from here.

I thought I should post this.

Thank you.

Luiz C. Vieira - Brazil

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